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Re: [extremeperl] Re: Testing, Audience, etc.

... Well, based on some work I did last night I have a prime example. I had written some modules previously that worked and are currently in production. Since

Message 1 of 20
, Feb 6, 2002

At 11:49 AM 2/6/2002 -0800, chromatic wrote:

>On Tuesday 05 February 2002 16:50, drewbie74 wrote:
>
> > How to convince people to wite tests? Chromatic's article on perl.com
> > was excellent in showing HOW to write tests. Perhaps we need an short
> > article showing exactly how tests made a project easier? Heck, I've
> > got time, maybe I'll put something together...
>
>How about some brainstorming then? Here are several benefits of writing
>tests, in no particular order:
>
> - to clarify the intent of the code
> - to enforce behavioral compatibility
> - to explore boundary conditions
> - to ensure that bugs have been corrected
> - to ensure that bugs remain corrected
> - to exercise an interface
> - to help with decoupling (when writing code for testability)
> - to add explanations of behavior (when using good test names with
>Test::More)
>
>There's obviously more (to make refactoring possible), but there's a
>disturbing tendency to rewrite software from scratch, and I'm picking my
>battles for now.
>
>-- c

Well, based on some work I did last night I have a prime example. I had
written some modules previously that worked and are currently in
production. Since there were no tests for said modules, I begun witing them
last night using Test::More (Thank you SO much Schwern - it rocks!). In the
process of doing so, I ended up doing some refactoring to make the modules
more flexible and worked out a couple of possible bugs. In the end, I had
better, more flexible, and refactored code that had good,comprehensive
tests - fulfilling the last 5 items in your list above. I was also forced
to setup a development environment (including a db) that had test data and
which I could use for testing purposes in perpetuity. This alone was worth
it's weight in gold.

For me, the acts of refactoring and writing tests now go hand in hand. Yes,
it takes time, sometimes a lot. But it is time well spent because it makes
your code better by the very nature of writing tests & making sure they
correctly run. It's hard to do one without the other because it's difficult
to make sure your "enhancement" isn't really a bug.

To address your last point, having tests helps keep me from rewriting code.
The tests help keep me from rewriting because I can fix only what is broken
or needs enhancing rather than thinking "This code is a bunch of crap!
Let's throw it out and just start over." Starting over is likely to
introduce more bugs than you fix. And this of course is exactly what you
were trying to avoid in the first place.

Oh geez, I hope I'm not becoming a zealot. Not that it would be a bad thing...

Well, based on some work I did last night I have a prime example. I had
written some modules previously that worked and are currently in
production. Since there were no tests for said modules, I begun witing them
last night using Test::More (Thank you SO much Schwern - it rocks!). In the
process of doing so, I ended up doing some refactoring to make the modules
more flexible and worked out a couple of possible bugs. In the end, I had
better, more flexible, and refactored code that had good,comprehensive
tests - fulfilling the last 5 items in your list above. I was also forced
to setup a development environment (including a db) that had test data and
which I could use for testing purposes in perpetuity. This alone was worth
it's weight in gold.

For me, the acts of refactoring and writing tests now go hand in hand. Yes,
it takes time, sometimes a lot. But it is time well spent because it makes
your code better by the very nature of writing tests & making sure they
correctly run. It's hard to do one without the other because it's difficult
to make sure your "enhancement" isn't really a bug.

To address your last point, having tests helps keep me from rewriting code.
The tests help keep me from rewriting because I can fix only what is broken
or needs enhancing rather than thinking "This code is a bunch of crap!
Let's throw it out and just start over." Starting over is likely to
introduce more bugs than you fix. And this of course is exactly what you
were trying to avoid in the first place.

Oh geez, I hope I'm not becoming a zealot. Not that it would be a bad thing...

... I like to distinguish between acceptance and unit tests. For unit tests, I would add: - to validate the API - to enable refactoring - to keep the cost of

Message 2 of 20
, Feb 6, 2002

Drew Taylor writes:

> At 11:49 AM 2/6/2002 -0800, chromatic wrote:
> >How about some brainstorming then? Here are several benefits of writing
> >tests, in no particular order:

I like to distinguish between acceptance and unit tests. For unit
tests, I would add:

- to validate the API
- to enable refactoring
- to keep the cost of change constant

A unit test suite is like a semantic compiler. In dynamic languages,
like Perl, there needs to be something to validate the code.

For acceptance tests, I would add:

- to encode concisely the domain knowledge of the customer
- to help the development team understand the problem

> Oh geez, I hope I'm not becoming a zealot. Not that it would be a bad thing...

Praise the Tests brother!

Rob

Drew Taylor

Could you explain a little more about the two types of tests you mention below? Specifically the acceptance tests, and how they would relate to web apps. I m

Message 3 of 20
, Feb 6, 2002

Could you explain a little more about the two types of tests you mention
below? Specifically the acceptance tests, and how they would relate to web
apps. I'm trying to become more of an "architect", so a lot of the "domain
knowledge" stuff you & other texts mention is still a little fuzzy to me. I
read some of the docs on bivio, and it sounded very interesting.
Unfortunately more of it than I wanted was over my head. I'm very intrigued
about the platform you released and how to learn more about it in the
future - it would be a great learning tool for me.

It sounds like the tests I wrote last night would be unit tests as they
test object instantiation & the APIs.

Drew

At 03:35 PM 2/6/2002 -0700, Rob Nagler wrote:

>I like to distinguish between acceptance and unit tests. For unit
>tests, I would add:
>
>- to validate the API
>- to enable refactoring
>- to keep the cost of change constant
>
>A unit test suite is like a semantic compiler. In dynamic languages,
>like Perl, there needs to be something to validate the code.
>
>For acceptance tests, I would add:
>
>- to encode concisely the domain knowledge of the customer
>- to help the development team understand the problem

One of the things I'm trying to learn is to become less of an architect.

> so a lot of the "domain
> knowledge" stuff you & other texts mention is still a little fuzzy
> to me.

Domain knowledge is simply "the problem". What I like about XP is
that it is problem-oriented, not solution-oriented.

> I
> read some of the docs on bivio, and it sounded very interesting.
> Unfortunately more of it than I wanted was over my head. I'm very intrigued
> about the platform you released and how to learn more about it in the
> future - it would be a great learning tool for me.

The great thing about perl is that lots of people have created lots of
code. We put out bOP, because it has no intrinsic value as a
product. There are just too many good toolkits out there. I consider
this a testament to perl more than anything else. You can create
incredibly solid software very quickly.

> It sounds like the tests I wrote last night would be unit tests as they
> test object instantiation & the APIs.

Yes, it sounds like you wrote unit tests. They are incredibly
important tools. We're slowly creating unit tests for our code. It's
tough to do, but we regret it every time we make changes and there is
no test to validate that we haven't broken anything.

Hope this helps.

Rob

Drew Taylor

... How do you do that? I ve only heard of tools that allow you to create a script and then playback that script. This is semiuseful, but what happens if you

Message 5 of 20
, Feb 6, 2002

At 10:52 PM 2/6/2002 -0700, Rob Nagler wrote:

>Drew Taylor writes:
> > Specifically the acceptance tests, and how they would relate to web
> > apps.
>
>What is beautiful about the Web is that HTTP and HTML are a messaging
>interface. You can build a complete acceptance test suite without
>dealing with GUI scripting.
>An acceptance test is a way of verifying end-user functions. A unit
>test verifies programmer level functions. Both can test Web software.

How do you do that? I've only heard of tools that allow you to create a
script and then playback that script. This is semiuseful, but what happens
if you make a change to the interface? What tools/techniques have you used
in the past to do acceptance testing? Do I have to setup a fake web server
environment & run the tests that way? That wouldn't be too difficult in a
CGI environment, and there are things like Apache::Fake now.

I hadn't seen that one before, although I have read some of Joel's other
articles. I'll read it tomorrow morning. My brief look says it will be
good. What I'm ultimately interested in learning is better design. Learning
patterns is one step, and working to see the problem from a higher level
view are two things I'm doing now.

> > so a lot of the "domain
> > knowledge" stuff you & other texts mention is still a little fuzzy
> > to me.
>
>Domain knowledge is simply "the problem". What I like about XP is
>that it is problem-oriented, not solution-oriented.

OK. Why don't they just say that? :-) I know that at high levels it's
essential that we're all speaking the same language, but can't that
language be simpler?

> > I
> > read some of the docs on bivio, and it sounded very interesting.
> > Unfortunately more of it than I wanted was over my head. I'm very
> intrigued
> > about the platform you released and how to learn more about it in the
> > future - it would be a great learning tool for me.
>
>The great thing about perl is that lots of people have created lots of
>code. We put out bOP, because it has no intrinsic value as a
>product. There are just too many good toolkits out there. I consider
>this a testament to perl more than anything else. You can create
>incredibly solid software very quickly.

This ability to quickly create a great product is one of the things that
really attracted me once I got serious about perl. I've seen several
frameworks that have interested me, including OpenInteract, OpenFrame, and
Mason. One day I hope I have the time to put some effort into learning each
better. I can just imagine all the tidbits of knowledge waiting to be
gleaned from each one.

> > It sounds like the tests I wrote last night would be unit tests as they
> > test object instantiation & the APIs.
>
>Yes, it sounds like you wrote unit tests. They are incredibly
>important tools. We're slowly creating unit tests for our code. It's
>tough to do, but we regret it every time we make changes and there is
>no test to validate that we haven't broken anything.

Yep, they were definitely unit tests. And as I mentioned before, I'm very
grateful I've written the ones I have because they did exactly what they're
supposed to do. Tell me when bugs appear and when they've been fixed. Once
I've gotten more tests done, I need to look into Test::Harness so I can run
them all at one swoop.

To illuistrate your last point, I have an example. At a previous employer,
we had a large codebase of perl modules (I bet it's probably doubled by
now) but no tests. I'm still close friends w/ the lead QA person and she
often just tests what she can and blindly hopes everything else still
works. It's just not possible to test every facet of the code for every
release (which is every 1-2 months). I really doubt that a comprehensive
test suite will ever be written, even though I have no doubt that it would
be an extremely important tool. The CTO's not convinced of the need, and I
don't think they would have/put the time to write a comprehensive suite
anyway. Besides, they're probably a little afraid of all the little bugs it
might turn up. ;-)

... If it s hidden, it s not hidden very well. :) Here s my take. Programmers don t want to write tests because: - it s not their job - it s not real

Message 6 of 20
, Feb 6, 2002

On Wednesday 06 February 2002 23:33, Drew Taylor wrote:

> The CTO's not convinced of the need, and I don't think they would have/put
> the time to write a comprehensive suite anyway. Besides, they're probably a
> little afraid of all the little bugs it might turn up. ;-)

- it takes time away from "real" coding
- QA should handle it
- it's cheaper to fix bugs when they're found

I'm only sympathetic to the coders who don't yet know how and those who think
writing tests is difficult. (I'll even propose that, unless you're adding
tests to a system that has none, it *shouldn't* be difficult. If it is,
you're not coding for testability and you're asking for trouble.)

Okay, my analyst hat is off. Feel free to jump on this thread with
evangelism if anyone has questions.

* * * * *

As for your Test::Harness question, use h2xs to make a skeleton Makefile.PL
for your project. Put your tests in the t/ subdirectory, edit the @INC paths
if needed, and run 'perl Makefile.PL; make; make test' and it should Just
Work.

Now you know just about as much as I care to remember about the whole process.

-- c

Drew Taylor

... All your points are right on the money. I would venture to guess that most good programmers would not be against writing tests. IMHO, it s usually

Message 7 of 20
, Feb 7, 2002

At 11:45 PM 2/6/2002 -0700, chromatic wrote:

><snip> excellent points </snip>

>I'm only sympathetic to the coders who don't yet know how and those who think
>writing tests is difficult. (I'll even propose that, unless you're adding
>tests to a system that has none, it *shouldn't* be difficult. If it is,
>you're not coding for testability and you're asking for trouble.)

All your points are right on the money. I would venture to guess that most
"good" programmers would not be against writing tests. IMHO, it's usually
managements edicts & timelines that forces the lack of tests. As for the
last point, I read somewhere (perhaps in one of Steve McConnell's books)
that a study found it takes magnitudes of more time/money to fix a bug
after the fact that to fix it before. And if it negatively affects a
customer, then multiply that cost by several factors for pissed off said
customer. If only management could be made to understand this fact, getting
tests would be much simpler. If I ever get a fulltime job again, I
certainly will push for good tests, even if it's just unit tests.

I was once one of those people who didn't understand how easy it is to
write tests. Yes, it took some time to get a good test environment setup,
but it was worth the few hous it took. And now I can easily and _quickly_
add new tests. Modules like Test::Simple & Test::More are the key.

>As for your Test::Harness question, use h2xs to make a skeleton Makefile.PL
>for your project. Put your tests in the t/ subdirectory, edit the @INC paths
>if needed, and run 'perl Makefile.PL; make; make test' and it should Just
>Work.

That's almost too easy... But then, this IS perl we're talking about. :-)

[OT] As an aside, why is it that when I do Reply TO All in Eudora that the
mailing list is on the to line twice, rather than the poster & the list?
It's rather annoying since that is my usual behavior. Or is this considered
bad form? I've never gotten a good answer on this question.

Hi all, ... [snip] ... See attached. I once had to fly to seven or eight different countries over a period of several weeks to fix a $0.25 problem in a couple

Message 8 of 20
, Feb 7, 2002

Hi all,

On Thu, 7 Feb 2002, Drew Taylor wrote:

> At 11:45 PM 2/6/2002 -0700, chromatic wrote:
[snip]
> managements edicts & timelines that forces the lack of tests. As for the
> last point, I read somewhere (perhaps in one of Steve McConnell's books)
> that a study found it takes magnitudes of more time/money to fix a bug
> after the fact that to fix it before. And if it negatively affects a
> customer, then multiply that cost by several factors for pissed off said
> customer. If only management could be made to understand this fact...

See attached.

I once had to fly to seven or eight different countries over a period
of several weeks to fix a $0.25 problem in a couple of hundred $22,000
instruments because the guy in procurement had ignored my written
procurement specification and the guy in test had ignored my written
test secification. The problems only started to surface when the
instruments were used in hot places.

It still bugs me that I didn't send a bill to their employer, who was
my supplier and contracted to make the things to the specification.

It's called experience.

73,
Ged.

[Non-text portions of this message have been removed]

Rob Nagler

... The first step is to make sure your interface has structure. If you are testing arbitrarily constructed templates, you re going to have a rough time. If

Message 9 of 20
, Feb 8, 2002

> How do you do that? I've only heard of tools that allow you to create a
> script and then playback that script. This is semiuseful, but what happens
> if you make a change to the interface?

The first step is to make sure your interface has structure. If you
are testing arbitrarily constructed templates, you're going to have a
rough time. If you build your HTML pages from widgets or
parameterized templates, you'll have some structure to grab on to.

> What tools/techniques have you used
> in the past to do acceptance testing?

The best tool is perl. We used it to test our CORBA based Web server,
and we use it to test our application written in perl. It is not very
hard to build an acceptance test suite using tools like LWP and
HTMLParser.

I am a little behind schedule. My goal is to release our internal
infrastructure by the end of the month. It will come with a test
suite which tests our pet shop demo (http://petshop.bivio.biz).

> Do I have to setup a fake web server
> environment & run the tests that way?

I find for acceptance testing you need a test environment which is as
close to your production environment as possible. Any of our
developers can run the test suite on their personal Web servers.
Every night we run the test suite against our test servers, which are
relatively clean machines.

> good. What I'm ultimately interested in learning is better design. Learning
> patterns is one step, and working to see the problem from a higher level
> view are two things I'm doing now.

To me, there are two sides: analysis and synthesis. Patterns are
about synthesis. XP is about analysis. I'm not a big fan of
patterns, because they're very focused on classical object-oriented
programming, and I try to program declaratively whenever I can. In
addition, languages like Java, have some serious deficiencies such as
weak ability to delegate and no class level inheritance.

I find reading books about Lisp, functional programming, and logic
programming expands my solution set much better than reading a book
about design patterns.

> OK. Why don't they just say that? :-) I know that at high levels it's
> essential that we're all speaking the same language, but can't that
> language be simpler?

It is really hard to write cogent prose, which addresses a wide
audience. They're just some concepts which are hard to explain in
simpler language. I'm reading a book by Einstein which is incredibly
well written but I have a really hard time understanding his
discussions about the special theory and general theory of
relativity. That's why I'm a programmer, I guess.

> anyway. Besides, they're probably a little afraid of all the little bugs it
> might turn up. ;-)
>
> Could this be a hidden reason some shops are wary of tests?

I don't think so. In general, people have a hard time quantifying
quality. If it works in the general case, it may be enough. The user
base may be small. I really like Gerry Weinberg's comments on quality
in his book "Quality Software Management: Vol. 1 Systems Thinking":

The Quality Statement: Every statement about quality is a statement about some
person(s).

The Political Dilemma: More quality for one person may mean less
quality for another.

The Quality Decision: Whose opinion of quality is to count when making
decisions?

The Inadequate Definition of Quality: Quality is the absence of error.

The Absence of Errors Fallacy: Though copious errors guarantees
worthlessness, having zero errors guarantees nothing at all about the
value of software.

I highly recommend the book.

Rob

Stas Bekman

... Since you are talking about testing apps against webserver, I d plug in the new Apache::Test framework which most Apache::* modules and frameworks

Message 10 of 20
, Feb 21, 2002

Rob Nagler wrote:

>>What tools/techniques have you used
>>in the past to do acceptance testing?
>>
>
> The best tool is perl. We used it to test our CORBA based Web server,
> and we use it to test our application written in perl. It is not very
> hard to build an acceptance test suite using tools like LWP and
> HTMLParser.
>
> I am a little behind schedule. My goal is to release our internal
> infrastructure by the end of the month. It will come with a test
> suite which tests our pet shop demo (http://petshop.bivio.biz).
>
>
>>Do I have to setup a fake web server
>>environment & run the tests that way?
>>
>
> I find for acceptance testing you need a test environment which is as
> close to your production environment as possible. Any of our
> developers can run the test suite on their personal Web servers.
> Every night we run the test suite against our test servers, which are
> relatively clean machines.

Since you are talking about testing apps against webserver, I'd plug in
the new Apache::Test framework which most Apache::* modules' and
frameworks' developers will find very helpful. The goal is to have every
Apache::* module needing mod_perl or just plain apache env, use
Apache::Test for its test. There is no more excuses for not having
tests. And if something is missing from its functionality now it's the
time to jump in and ask for it/add it.

httpd-test project is using this Perl framework for testing C modules
for Apache 1.3 and 2.0 and the server itself. And of course originally
it was developed for mod_perl 2.0. The same test suite can work with
httpd 1.3 and httpd 2.0. For more info see:
http://perl.apache.org/preview/modperl-site/docs/2.0/devel/testing/testing.html

Once we release the new modperl site (hopefully in a few weeks) this URL
will appear as:
http://perl.apache.org/docs/2.0/devel/testing/testing.html

I've started mentioning XP in this doc and mention reasons for a need to
test, but more work in needed so your help is very welcome.

To get the framework grab the httpd-test rep from cvs or the snapshot:
http://cvs.apache.org/snapshots/modperl-2.0/

also see:
http://cvs.apache.org/viewcvs.cgi/httpd-test/perl-framework/README?rev=1.8&content-type=text/vnd.viewcvs-markup